Unitary Solderless Monopole Antenna for in-duct use

ABSTRACT

An improved monopole antenna for in-duct use is disclosed. The antenna comprises a center pin rod disposed coupled to a connector housing by a molded dielectric. The center pin rod includes a pin portion which is disposed through a portion of a connector portion of the connector housing, thereby allowing a mating RF connector to couple to the monopole antenna. The center pin rod is composed of a single assembly or a single piece of material, thereby eliminating the need to solder the antenna to a RF connector.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119(e) from U.S.Provisional Patent Application Number 61/095,135, entitled “UNITARYSOLDERLESS MONOPOLE ANTENNA FOR IN-DUCT USE,” filed on behalf ofinventors Paul Barter and Rudy Ruelas on Sep. 8, 2008.

FIELD OF THE INVENTION

The present invention relates generally to antenna, and moreparticularly to antenna for use within the duct system of a building,and more particularly still to a monopole antenna for use within theduct system of a building.

DESCRIPTION OF THE PRIOR ART

A monopole antenna is a type of simple radio antenna formed by replacinga portion of a dipole antenna with a ground plane at a right-angle tothe remaining portion. If the ground plane is sufficiently large, amonopole antenna will behave similarly to a comparable dipole antenna.The use of monopole antennas and their characteristics are well known inthe art. For example, many radio broadcast antennas are monopoleantennas. Similarly, whip antennas, widely used in handheld radios, arealso monopole antennas.

FIG. 1 discloses a monopole antenna that was used within the heating,cooling, and ventilation duct system of a building (“in-duct”) forreception and transmission of radio signals. As can be seen, the priorart monopole antenna was coupled to the duct through the use of a clipmechanism that engaged the interior of the duct through a hole that wascut into the exterior of the duct. The antenna also included aconductive rod formed such that it was one-quarter wavelength of thedesired frequency that the monopole antenna was designed to receive andtransmit. The rod was joined to a SMA connector by a solder dot. Whilethe prior art in-duct monopole antenna was operable, there are a numberof shortcomings that it does not address. First, the prior art antennawas expensive to manufacture, in that it required hand-soldering of theSMA connector to the rod and the solder caused an unpredictable voltagestanding wave ratio. Second, the prior art antenna was difficult toinstall, as it required a precise hole to be cut in the exterior of theduct, so that the clip mechanism could properly engage the duct and holdthe antenna in place. Third, improper formation of the mounting holecould cause moisture, which tends to accumulate within ducts, to leakout of the duct. Fourth, the ground plane was too thick to be bent andreliably connect to a round duct. Fifth the ground plane was notpermanently mounted and easily dislodged from the duct.

OBJECTS OF THE INVENTION

Accordingly, it is an object of this invention to provide an improvedmonopole antenna for use within the duct system of a building.

Another object of the invention is to provide an in-duct monopoleantenna that is inexpensive to manufacture;

Another object of the invention is to provide an in-duct monopoleantenna that is simple to install;

Another object of the invention is to provide an in-duct monopoleantenna that does not create leaks from the duct system;

Other advantages of the disclosed invention will be clear to a person ofordinary skill in the art. It should be understood, however, that asystem, method, or apparatus could practice the disclosed inventionwhile not achieving all of the enumerated advantages, and that theprotected invention is defined by the claims.

SUMMARY OF THE INVENTION

The disclosed invention achieves its objectives by providing a monopoleantenna adapted for in-duct use comprising a connector housing formounting to a flat bendable metal surface through one or more screwholes. The connector housing comprises a flat, bendable portionincluding the screw holes and a connector portion having a hollowinterior. The connector portion may comprise a series of threads adaptedto couple with a reverse polarity female SMA, N or other size orthreaded coaxial connector, or may be adapted to couple with some otherform of RF connector. The monopole antenna further comprises a centerpin rod including an antenna portion, a mounting portion, and a pinportion. The antenna portion is generally sized to transmit and receivea particular desired wavelength corresponding to the type of signal withwhich the monopole antenna will be used. The pin portion is disposed sothat it will comprise the center conductor of the connector formed withthe connector portion of the connector housing. A molded dielectric,such as a fluoropolymer resin, is formed about the mounting portion ofthe center pin rod and a portion of the connector portion of theconnector housing. A sufficient length of the pin portion of the centerpin rod is exposed to mate with a corresponding RF connector. The centerpin rod is formed of a single piece of material, or is a singleassembled component, thereby eliminating the step of soldering theantenna portion to an RF connector.

BRIEF DESCRIPTION OF THE DRAWINGS

Although the characteristic features of this invention will beparticularly pointed out in the claims, the invention itself, and themanner in which it may be made and used, may be better understood byreferring to the following description taken in connection with theaccompanying drawings forming a part hereof wherein like referencenumerals refer to like parts throughout the several views and in which:

FIG. 1 is a perspective view of a prior art antenna used for in-ductreception and transmission of radio signals;

FIG. 2 is a side view of an improved monopole antenna for in-ductreception and transmission of radio signals;

FIG. 3 is an exploded side view of the improved monopole antenna of FIG.2;

FIG. 4 is a side view of the rod/center conductor component used by theimproved monopole antenna of FIG. 2;

FIG. 5 is an exploded side view of the center conductor portion of therod/center conductor component depicted by FIG. 4,

FIG. 6 is a side view of the rod/center conductor component after afluoropolymer resin dielectric has been injection molded about thenarrow portion of the rod;

FIG. 7 is an exploded side view of the assembly of FIG. 6;

FIG. 8 is a side view of the connector portion of the improved monopoleantenna of FIG. 2;

FIG. 9 is a side view of an SMA connector used by the connector portiondepicted by FIG. 8;

FIG. 10 is a bottom view of the connector portion depicted by FIG. 8;

FIG. 11 is an exploded side view of the connector portion depicted byFIG. 8; and

FIG. 12 is a bottom view of a mounting plate used in conjunction withthe improved monopole antenna of FIG. 2.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

Turning to the Figures, and to FIG. 2 in particular, a monopole antenna100 constructed in accordance with the disclosed invention is depicted.The depicted monopole antenna 100 comprises a center pin rod 102 formedwith a length adapted to be one-quarter of the wavelength of the signalthe monopole antenna 100 is intended to transmit and receive. The centerpin rod 102 is formed of a non-combustible and corrosion resistantmaterial, such as gold plated brass. The center pin rod 102 is coupledto an injection molded fluoropolymer resin dielectric 112. The low-smokeproducing fluoropolymer resin dielectric 112 provides spacing betweenthe center pin rod 102 and a flat, bendable mounting plate 108. Theflat, bendable mounting plate 108 is coupled to a connector housing 104by a series of screws 107. The connector housing 104 is formed as asingle piece including a flat bendable portion 105 and a connectorportion 106. The connector housing is formed of 18-24 gauge galvanizedsteel. The connector portion may be formed to accept, for example, areverse polarity SMA (SubMiniature version A) socket. The connectorhousing may be formed of gold plated brass, or some other appropriatematerial.

As explained herein, the monopole antenna 100 is installed into a ductsystem by drilling a small hole sized to accept the center pin rod 102,inserting the center pin rod 102 through the hole, and screwing theflat, bendable mounting plate 108 to the duct. Caulk may be used to sealthe hole through which the center pin rod 102 is inserted.

FIG. 3 depicts an exploded side view of the disclosed improved monopoleantenna 100. The center pin rod 102 actually comprises three portions;an upper antenna portion 111, a center mounting portion 103, and a lowerpin portion 110. By forming the center pin rod 102 of a single piece ofmaterial or component with three separate portions, the step ofsoldering the center pin rod 102 to an SMA connector is eliminated. FIG.3 also shows how the injection molded fluoropolymer resin dielectric 112is formed about the mounting portion 103 of the center pin rod 102through most of the connector portion 106 of the connector housing 104,leaving only a small amount of the lower pin portion 110 exposed forcoupling with an SMA socket.

FIG. 4 most clearly depicts the construction of the center pin rod 102used in the disclosed improved monopole antenna. While the center pinrod 102 is formed of a single piece of material, such as gold platedbrass or simply brass, it comprises three separate portions. The antennaportion 111 is sized to be one-quarter the wavelength of the signalwhich the monopole antenna will transmit and receive. The mountingportion 103 is narrower than the antenna portion 102 to allow theacceptance of an injection molded dielectric, such as a fluoropolymerresin. The pin portion 110 is sized to mate with a female reversepolarity SMA socket or other RF connector, and sufficiently long toextend through the injection molded dielectric and couple with theaforementioned socket.

FIG. 5 depicts the dimensions of the tip of the pin portion 110 of thecenter pin rod used in the disclosed improved monopole antenna.

FIG. 6 depicts the center pin rod 102 encapsulated by the injectionmolded dielectric 112.

FIG. 7 depicts an exploded view of the center pin rod 102 encapsulatedby the injection molded dielectric 112. As shown, the dielectric 112surrounds the mounting portion 103 of the center pin rod 102, as well aspart of the pin portion 110.

FIG. 8 depicts the connector housing 104 used with the disclosedimproved monopole antenna. As illustrated, the connector housing 104 iscomprised of a single piece of material. The material may be, forexample, 18-24 gauge galvanized steel, or gold plated brass. Theconnector housing 104 includes a flat but bendable portion 105 and aconnector portion 106. The connector portion 106 may include a series ofthreads to accept a mating connector, such as, for example, a reversepolarity SMA socket.

FIG. 9 depicts one possible set of dimensions of the connector portion106 of the connector housing 104 depicted in FIG. 8.

FIG. 10 depicts one possible set of dimensions of the flat portion 105of the connector housing 104 depicted in FIG. 8. As illustrated, theflat portion 105 is mounted to the flat, bendable mounting plate (notshow in FIG. 10) by a series of four screws using the screw holes 117.

FIG. 11 depicts an exploded side view of the connector housing 104,showing one possible set of dimensions for various portions.

FIG. 12 depicts the flat, bendable mounting plate 108 used for mountingthe disclosed monopole antenna to a duct system. The flat, bendablemounting plate 108 includes a center hole 119 sized to accept the centerpin rod of the monopole antenna. In addition, a series of screw holes117 is used to connect the flat, bendable mounting plate 108 to theconnector housing. Further, a second series of screw holes 121 is usedto connect the flat, bendable mounting plate to a duct system.

The foregoing description of the invention has been presented forpurposes of illustration and description, and is not intended to beexhaustive or to limit the invention to the precise form disclosed. Thedescription was selected to best explain the principles of the inventionand practical application of these principles to enable others skilledin the art to best utilize the invention in various embodiments andvarious modifications as are suited to the particular use contemplated.It is intended that the scope of the invention not be limited by thespecifications but be defined by the claims set forth below.

1. A monopole antenna for in-duct transmission and reception of asignal, said monopole antenna comprising: i) a connector housingincluding a flat portion adapted to mount to a metal surface and aconnector portion having a hollow interior; ii) a center pin rod havingan antenna portion with a length adapted to transmit and receive saidsignal, said center pin rod further having a mounting portion and a pinportion disposed within said connector portion of said connectorhousing, said center pin rod further comprising a single component; andiii) a molded dielectric formed around said mounting portion of saidcenter pin rod and partially through said connector portion of saidconnector housing.
 2. The monopole antenna of claim 1, furthercomprising a mounting plate disposed so that said connector housing iscoupled to a first side of said mounting plate and said center pin rodextends from a second side of said mounting plate.
 3. The monopoleantenna of claim 2, wherein said mounting plate comprises four mountingholes disposed about a periphery of said mounting plate.
 4. The monopoleantenna of claim 3, wherein said mounting holes are each adapted toaccept a screw and further adapted to couple said mounting plate to theexterior of a duct system using said screws.
 5. The monopole antenna ofclaim 1, wherein said center pin rod is comprised of brass.
 6. Themonopole antenna of claim 1, wherein said center pin rod is comprised ofgold plated brass.
 7. The monopole antenna of claim 1, wherein saidmolded dielectric is comprised of a fluoropolymer resin.
 8. The monopoleantenna of claim 1I wherein said connector portion further comprises aseries of threads adapted to couple with an SMA connector.